The present invention relates to an improved key mechanism for a bass range clarinet, and more particularly relates to improvements in construction of a key mechanism for controlling tone generation by a bass range clarinet such as an alto clarinet, a bass clarinet, a contraclarinet or a basset horn.
A bass range clarinet is a sort of wood wind made of granadilla or the like and in general is in the form of a long tubular body. An axial hole for air column vibration is formed through the tubular body in communication with surrounding air via radial tone holes formed at prescribed positions along the length of the tubular body and tone generation via each tone hole is controlled by an associated key mechanism arranged on the tubular body. More specifically, the key mechanism includes a key corresponding to a tone hole. The key is mechanically linked to a pad arm via a key post secured to the tubular body near the tone hole and a pad means is swingably carried by the pad arm. The pad means is spring loaded to normally open the tone hole and closes the tone hole when the key is manually operated in order to adjust the length of the air column to be generated in the axial hole.
When compared with brasses, tone holes in a bass range clarinet are smaller in dimension. In addition, the pad is allowed to swing only over a limited angle. That is, even in an open state of a tone hole, the associated pad is located just above the open tone hole. Thus, at tone generation under this condition, the sound wave is reflected by the face of the pad back into the axial hole in the tubular body and poses ill influence on the air column vibration. In other words, the peak frequency of the air column vibration is much disturbed by the reflected sound wave, thereby degrading sound emanation of the bass range clarinet while allowing generation of gloomy tones.
With the conventional key mechanism, sound emanation is much degraded in the case of an A/E note, a Bb/F note and a B/F.music-sharp. note. Such notes are accompanied with a mode quite like the so-called throat tones. Tone holes for such notes are located quite close to the throat of a bass clarinet whereat the air column vibration can hardly be stabilized. Such throat tones are very sonant and also poor in sound emanation.